2 Commonly Used Methods for Constructing a Flat Roof


Flat roofs are a common feature of many commercial buildings in areas that don't receive regular snowfall in winter. Yet even in such regions, many people fail to understand the basic materials used to construct a flat room. If you own a business or commercial property with a flat roof and are curious to learn more about it, read on. This article will discuss two common methods of constructing a flat roof.

Built-up Roofing

Built-up roofing involves the application of multiple layers of roofing material—literally "building up" the roof, layer by layer. There are two principal materials involved in each layer. First, there is the so-called underlayment, which generally consists of roofing paper. The second element is hot asphalt tar. The idea is that while a single such layer would not be able to provide adequate protection against water, multiple layers overlap in such a way as to provide an efficient and highly durable barrier. 

To provide reliable protection, most built-up roofs consist of either three or four layers. Whereas three-layer roofs have a lifespan of between 10 and 14 years, a four-layer built-up roof can be expected to last between 14 and 22 years. Given the extensive installation process associated with a built-up roof, the added expense of a four-layer roof tends to be worth it, since it will defer both the timing as well as the inconvenience of its eventual replacement. 

Membrane Roofing

Rubber membrane roofing was developed as a way to cut down on the lengthy installation process of a built-up roof. Here, rather than successive layers of asphalt and roofing paper, there is just a single sheet of waterproof material. This sheet can be made from a variety of different materials, including:

  • PVC
  • chlorinated polyethylene
  • neoprene
  • polymer-modified bitumen
  • ethylene propylene diene monomer

Perhaps the most frequently used membrane roofing material is ethylene propylene diene monomer, also known as EPDM. EPDM is a type of synthetic rubber. It comes in a gigantic rolled-up sheet that must be cut down the size of a particular roof. The particular advantage of EPDM, if you haven't already guessed it, is that only one layer is necessary in order to fully waterproof a roof. This greatly reduces the cost of the roofing, both by lowering the amount of materials needed and by cutting down on the time and manpower required for installation. 

EPDM offers a number of distinct advantages aside from expense and installation time. EPDM roofs have an approximate lifespan of between 22 and 35 years. Additionally, EPDM roofs do not pollute the rainwater that passes over them. This is a problem with built-up roofs and other types of roofs that contain large quantities of asphalt. The chemically inert nature of an EPDM roof means that rainwater can be effectively gathered and reused for such purposes as irrigation, cleaning, and even personal hygiene. 

Talk to a contractor such as Specialty Commercial Contractors Llc for more information about different types of roofing. 

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A few years ago, our roof started to have all kinds of problems. The shingles were perpetually blowing off, and I could tell that there were some underlying rot issues. We could see mold and moss from street level, and so I called in the professionals. Our professional roofing team took the time to get up on the roof, inspect the damage, and recommend repairs. They were incredibly easy to work with, and I was really impressed by their professionalism. This blog is all about things to look for when it comes to your roof and tips for finding an incredible roofer.